CVE-2020-26890 log

Severity High
Remote Yes
Type Denial of service
Matrix Synapse before 1.20.0 erroneously permits non-standard NaN, Infinity, and -Infinity JSON values in fields of events, allowing remote attackers to execute a denial of service attack against the federation and common Matrix clients. If such a malformed event is accepted into the room's state, the impact is long-lasting and is not fixed by an upgrade to a newer version, requiring the event to be manually redacted instead. Since events are replicated to servers of other room members, the impact is not constrained to the server of the event sender.
Group Package Affected Fixed Severity Status Ticket
AVG-1296 matrix-synapse 1.19.1-1 1.20.1-1 High Fixed
Date Advisory Group Package Severity Type
26 Nov 2020 ASA-202011-23 AVG-1296 matrix-synapse High denial of service